JP2007170244A - Muffler for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for a vehicle which can secure an outer tube 4, an inner tube 1 and connecting tubes 2, 3 at the same time without welding and increase sealability among the tubes. <P>SOLUTION: The inner tube 1 includes mountain-shaped bead portions 1a, 1b formed at end portions thereof and protruding outward in the radial direction. The connecting tubes 2, 3 respectively include diameter-increased flared portions 2a, 3a formed at end portions thereof. The bead portions 1a, 1b of the inner tube 1 are inserted into the flared portions 2a, 3a of the connecting tubes 2, 3 and brought into contact with inner sides thereof, and end portions of the outer tube 4 are arranged adjacently to outer sides of the bead portions 1a, 1b and the flared portions 2a, 3a. The end portions of the outer tube 4 are reduced in diameter by spinning so as to be crimped and fastened to the outer peripheries of the connecting tubes 2, 3, and at the same time, parts of the diameter-reduced inclined portions are crimped in conformity with and secured to the outer peripheries of the flared portions 2a, 3a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a muffler for a vehicle.

2. Description of the Related Art Conventionally, a vehicle silencer technique in which an end portion of an outer tube that has been reduced in diameter by drawing spinning is fixed to an inner tube by welding is known (see Patent Document 1).
Japanese Patent Laid-Open No. 10-280953

  However, in recent years, the exhaust pipe including the outer pipe and the inner pipe has been reduced in thickness mainly for the purpose of reducing the weight, and there is a problem that the end of the outer pipe is blown when attempting to weld the end of the outer pipe to the inner pipe. there were.

  The present invention has been made in order to solve the above-mentioned problems. The object of the present invention is to fix the outer tube, the inner tube and the connecting tube at the same time without using welding, and to improve the sealing performance of these three components. It is to provide a vehicle silencer that can be increased.

  According to the first aspect of the present invention, an angled bead portion bulging radially outward is formed at both end portions of the inner tube, and is expanded at the end portions of the connecting tubes respectively connected to both end portions of the inner tube. A flare portion is formed, and the bead portions of the inner pipes are inserted into and contacted with the inner side of the corresponding flare portions of the connecting pipes, respectively, and the outer pipes are adjacent to the outer sides of the bead portions and the flare portions. Corresponding end portions are arranged, and both end portions of the outer tube are reduced in diameter by drawing and spinning, and at the same time, a part of the inclined portion reduced in diameter is swaged and fixed to the outer periphery of the corresponding flare portion. Features.

  In the first aspect of the present invention, the end portions of the connecting pipes that are formed with angle-shaped bead portions bulging outward in the radial direction at both end portions of the inner tube and are respectively connected to both end portions of the inner tube The inner pipe bead portions are inserted into and contacted with the inner side of the corresponding flare portions of the corresponding connecting pipes, and the outer bead portions and the flare portions are disposed close to the outer sides of the flare portions. Place the corresponding ends of the pipes and reduce the diameter of both ends of the outer pipe by drawing and spinning, and at the same time, squeeze some of the reduced diameter inclined parts to the outer peripheries of the corresponding flare parts. Therefore, the inner tube, the connecting tube, and the outer tube can be fixed at the same time during the drawing spinning process without using welding.

  Further, the flare portion and the bead portions 1a and 1b can be crimped to the radially inner side and the axially inner side at the end portion of the outer tube, and the sealing performance of the inner tube, the connecting tube, and the outer tube can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1 will be described below.
FIG. 1 is a half sectional view of a vehicle silencer according to the first embodiment of the present invention, FIG. 2 is an enlarged view of a main part of the first embodiment, and FIGS. 3 to 5 illustrate the manufacture of the vehicle silencer according to the first embodiment. 6 and 6 are diagrams for explaining an exhaust system to which the vehicle silencer of the first embodiment is applied.

First, the overall configuration will be described.
As shown in FIG. 1, the vehicle silencer A of the first embodiment is provided with an inner tube 1, connecting tubes 2 and 3, and an outer tube 4, which are all made of metal and have a thickness of about 1 mm. And has a substantially cylindrical shape.

At both ends of the inner tube 1, chevron shaped bead portions 1 a and 1 b that bulge outward in the radial direction are formed.
In addition, a plurality of punching holes 1c formed of circular small holes are formed in the middle portion of the inner tube 1. Note that the shape, number of formation, and formation position of the punching hole 1c can be set as appropriate.
Flares 2a and 3a are formed at the ends of the connecting pipes 2 and 3, respectively.

And the bead parts 1a and 1b of the inner pipe 1 are inserted into and contacted with the inner sides of the flare parts 2a and 3a of the corresponding connecting pipes 2 and 3, respectively. A room R1 is formed between the inner tube 1 and the outer tube 4 by fixing the corresponding end portions in contact with each other.
Specifically, as shown in FIG. 2, the inner tube 1 is connected at both ends thereof from the flat portion 5 to the inclined portion 6 on one side of the bead portion 1a (1b) corresponding to the outer periphery thereof. A part of the flat part 7 of the tube 2 (3) and the inner periphery of the flare part 2a (3a) are in close contact with each other, and the flat part of the connecting pipe 2 (3) is connected from each flare part 2a (3a). 7 is fixed in a state where the inner periphery of the flat portion 9 of the outer tube 4 is in close contact with a part of the inclined portion 8 of the outer tube 4 corresponding to the outer periphery of the portion 7.

  Note that the protruding lengths of the flare portions 2a, 3a and the bead portions 1a, 1b can be set as appropriate. The thicknesses of the inner tube 1, the outer tube 4, and the connecting tubes 2 and 3 can be set as appropriate.

Next, the operation will be described.
When the vehicle silencer A constructed as described above is manufactured, first, bead portions 1a and 1b are formed at both ends of the inner tube 1, and a flare portion 2a is formed at the ends of both connecting tubes 2 and 3. , 3a is formed.

Next, as shown in FIGS. 3 and 4, after the inner tube 1 is arranged inside the outer tube 4 before molding, the outer periphery of which is fixed by a pair of upper and lower jigs X1 and X2, the connecting tube 2 is connected from both sides thereof. 3 is inserted, and the bead portions 1a and 1b of the inner pipe 1 are inserted into and contacted with the flare portions 2a and 3a of the corresponding connecting pipes 2 and 3, respectively. The inner tube 1 is held by a jig not shown.
At this time, the end portion of the outer tube 4 before molding is arranged in the vicinity of the outside of the bead portions 1a and 1b and the flare portions 2a and 3a.

Next, as shown in FIG. 5, at both ends of the outer tube 4 before molding, the pair of disk-shaped rotating rollers 11 a and 11 b rotating in the direction of the arrow A <b> 1 are pressed against the outer periphery of the outer tube 4. And moving from the reciprocating motion in the direction of the arrow A2 to a moving locus that gradually matches the outline of the outer tube 4 to be manufactured, and drawing and spinning the outer tube 4, thereby forming the desired vehicle silencer. A is obtained (see FIG. 1).
At this time, the flat portions 9 at both ends of the outer tube 4 are fixed by caulking to the outer peripheries of the corresponding connecting tubes 2 and 3, respectively, and at the same time, a part of the inclined portion 8 having a reduced diameter is fixed to the outer peripheries of the flare portions 2a and 3a. The flared portions 2a and 3a and the bead portions 1a and 1b can be crimped radially inward and axially inward at both ends of the outer tube 4 by being crimped along the inner tube 1, the inner tube 1, the connecting tube 2, 3. The sealing performance of the outer tube 4 can be increased.

  In addition, a reaction force against the stress in the diameter reduction direction in the above-described draw spinning process is obtained from the chevron shape of the bead parts 1a and 1b, and thereby the bead parts 1a and 1b are not buckled, and the inside of the flare parts 2a and 3a. It acts so that it adheres more.

  In the first embodiment, the flat portions 9 at both ends of the outer tube 4 are fixed by crimping on the outer periphery of the corresponding connecting tubes 2 and 3, respectively. Therefore, the sealing performance between the outer tube 4 and the connecting tubes 2 and 3 is improved. Further improvement can be achieved.

Therefore, the inner pipe 1, the connecting pipes 2, 3, and the outer pipe 4 can be fixed at the same time when the outer pipe 4 is subjected to drawing spinning, and the equipment and time required for these fixing operations can be greatly reduced.
In addition, since welding is not used compared to the conventional invention, stable fixing is possible even if the inner tube 1, connecting tubes 2, 3, and outer tube 4 are thinned (for example, the thickness is 1 mm or less). Can improve the reliability.

  As shown in FIG. 6, the vehicle silencer A manufactured in this way includes an exhaust manifold 16 connected to the cylinder head of the engine 15, a catalytic converter 17, a sub muffler 18, and a main muffler 19. Among the exhaust systems, it is adopted as a sub-muffler 18. At this time, as shown in FIG. 1, exhaust gas (shown by broken line arrows) flows from the connecting pipes 2, 3 to the inner pipe 1 to the connecting pipes 2, 3. While being discharged, a part of the exhaust gas (sound energy) is introduced into the room R1 through the punching hole 1c, and a predetermined resonance frequency is generated to reduce the exhaust noise.

Next, the effect will be described.
As described above, in the muffler A for a vehicle according to the first embodiment, the angled bead portions 1a and 1b bulging outward in the radial direction are formed at both ends of the inner tube 1, and the inner tube 1 Flared portions 2a and 3a are formed at the ends of the connecting pipes 2 and 3 connected to both ends of the inner pipe 1, and the bead portions 1a and 1b of the inner pipe 1 are respectively connected to the corresponding flare portions of the connecting pipes 2 and 3. 2a and 3a are inserted and brought into contact with each other, and the corresponding end portions of the outer tube 4 are arranged close to the outside of the bead portion and the flare portions 2a and 3a. Since the diameter of the inclined portion 8 is reduced by the drawing spinning process, and part of the reduced inclined part 8 is fixed by crimping to the outer periphery of the corresponding flare part 2a, 3a, the drawing spinning process of the outer tube 4 without using welding. Sometimes the inner tube 1, the connecting tubes 2, 3 and the outer tube 4 can be fixed simultaneously.

  In addition, the flare portions 2a, 3a and the bead portions 1a, 1b can be crimped radially inward and axially inward at both ends of the outer tube 4, and the sealing performance of the inner tube 1, the connecting tubes 2, 3, and the outer tube 4 is high. it can.

Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.
For example, the internal structure of the outer tube 4 can be set as appropriate. As shown in FIG. 7, a sound absorbing material 20 may be interposed in a room R1 inside the outer tube 4 to function as a sound absorbing chamber.
In addition, as shown in FIG. 8, the sound absorbing chamber R <b> 2 and the resonance chamber R <b> 3 including the sound absorbing material 20 may be formed by partitioning the inside of the outer tube 4 with a baffle plate 21.

  Furthermore, the vehicle silencer of the present invention is not limited to a sub-muffler, but can be applied to an exhaust-type main muffler or the like.

It is a half sectional view of the silencer for vehicles of Example 1 of the present invention. FIG. 3 is an enlarged view of a main part of the first embodiment. It is a figure explaining manufacture of the vehicle silencer of the present Example 1. FIG. It is a figure explaining manufacture of the vehicle silencer of the present Example 1. FIG. It is a figure explaining manufacture of the vehicle silencer of the present Example 1. FIG. It is a figure explaining the exhaust system to which the vehicle silencer of the present Example 1 is applied. It is a half sectional view of a silencer for vehicles of other examples. It is a half sectional view of a silencer for vehicles of other examples.

Explanation of symbols

R1 Room X1, X2 Jig 1 Inner tube 1a, 1b Bead portion 2, 3 Connection tube 2a, 3a Flare portion 4 Outer tube 5 (Bead portion) Flat portion 6 (Bead portion) Inclined portion 7 (Connection tube) Flat part 8 (outer pipe) inclined part 9 (outer pipe) flat part 11a, 11b Rotating roller 15 Engine 16 Exhaust manifold 17 Catalytic converter 18 Sub muffler 19 Main muffler

Claims (1)

A chevron shaped bead bulging radially outward is formed at both ends of the inner tube,
Form a flared portion that expands at the end of the connecting pipe connected to each end of the inner pipe,
The inner pipe bead portions are inserted into and contacted with the inner side of the corresponding flare portions of the connection pipes, and the corresponding end portions of the outer pipes are disposed in proximity to the outer sides of the bead portions and the flare portions. ,
A muffler for a vehicle characterized in that both ends of the outer tube are reduced in diameter by drawing and spinning, and at the same time, a part of the reduced inclined portion is crimped and fixed to the outer periphery of the corresponding flare portion.

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